There has been known an image forming apparatus of an electrophotographic type in which a photosensitive member unit having a photosensitive member for forming a developer image thereon is removably mounted.
For example, a laser printer has an image forming unit which holds four process units for black, yellow, magenta and cyan, respectively (for example, refer to JP-A-2010-2626).
In this laser printer, the image forming unit has a notched part, which is notched forward, at a rear end thereof, and a support shaft, which protrudes outward in the left-right direction, at a front end thereof.
The body frame includes a body reference shaft, to which the notched part of the image forming unit is engaged, a support shaft insertion hole, into which the support shaft of the image forming unit is engaged, and a lock member which presses the support shaft rearward in conjunction with a closing operation of a door of the body frame.
In this laser printer, when the image forming unit is transported while being accommodated in the body frame at shipment of the laser printer, for example, the image forming unit may rattle due to shock from the outside during the transport.
Therefore, in order to buffer the shock from the outside, it is considered to fill a buffer material of foamed polystyrene and the like between the image forming unit and the body frame.
In this case, however, it is necessary to remove all the buffer material when setting up the laser printer, so that the setup operation of the laser printer would be cumbersome.